Middle Eocene Trees of the Clarno Petrified Forest, John Day Fossil Beds National Monument, Oregon

Home , Macginitiea

ELISABETH A. WHEELER1 and STEVEN R. MANCHESTER2 1Department of Forest Biomaterials, North Carolina State University, Raleigh, NC 27605-8005 USA; elisabeth_ [email protected]. 2Florida Museum of Natural History, University of Florida, Gainesville, FL 32611 USA; steven@ flmnh.ufl.edu

One of the iconic fossils of the John Day Fossil Beds National Monument, Oregon, USA, is the Hancock Tree—a permineralized standing tree stump about 0.5 m in diameter and 2.5 m in height, embedded in a lahar of the Clarno Formation of middle Eocene age. We examined the wood anatomy of this stump, together with other permineralized woods and leaf impressions from the same stratigraphic level, to gain an understanding of the vegetation intercepted by the lahar. Wood of the Hancock Tree is characterized by narrow and numerous vessels, exclusively scalariform perforation plates, exclusively uniseriate rays, and diffuse axial parenchyma. These features and the type of vessel-ray parenchyma indicate affinities with the Hamamelidaceae, with closest similarity to the Exbucklandoideae, which is today native to Southeast and East Asia. The Hancock Tree is but one of at least 48 trees entombed in the same mudflow; 14 others have anatomy similar to the Hancock Tree; 20 have anatomy similar to Platanoxylon haydenii (Platanaceae), two resemble Scottoxylon eocenicum (probably in order Urticales). The latter two wood types occur in the nearby Clarno Nut Beds. Two others are distinct types of dicots, one with features seen in the Juglandaceae, the other of unknown affinities, and the rest are very poorly preserved and of unknown affinity. Leaf impressions in and immediately below the layer containing the trees include the extinct genera Macginitiea and Platimeliphyllum (Platanaceae), and Trochodendroides (Saxifragales).

Keywords: Eocene, Clarno Formation, paleobotany, fossil wood, Hamamelidaceae, Platanaceae, wood anatomy

INTRODUCTION considered to have been deposited subsequent to the folding, The Nut Beds locality in the Clarno Formation of north- faulting, intrusion and erosion of the strata that include the central Oregon contains one of North America’s most diverse Nut Beds (his unit B). Whereas the Hancock Canyon lahar and well-documented assemblages of middle Eocene plants, contains large tuffaceous clasts up to 30 cm in diameter, with fruits, seeds, leaves, and woods (Scott 1954, Manchester clasts in the Nut Beds deposits generally do not exceed five 1981, Manchester 1994, Wheeler and Manchester 2002). cm. Although woods of the Nut Beds are highly abraded and About two km east of the Nut Beds in Hancock Canyon, evidently allochthonous (i.e., transported), those of Hancock Wheeler County, and in what is today the John Day Fossil Canyon are logs and stumps with minimal abrasion and may Beds National Monument, there is a petrified forest preserved represent more or less in situ forest intercepted by a lahar. in a volcanic lahar. Compared to the Nut Beds the quantity The botanical affinities of the Hancock Canyon trees have and diversity of the Hancock Canyon woods is low, but there not been examined in detail. Here we provide an overview of are logs and standing trunks up to 60 cm diameter contrast- the wood anatomical types occurring in the Hancock Canyon ing with the fragmentary eroded woods of the Nut Beds. area, and document associated leaf impressions. This informa- One of the large standing trunks, visible along the US Park tion will further our understanding of the diversity of woody Service’s Hancock Canyon trail, is named the Hancock Tree. plants in the Eocene of northwestern North America, as well This canyon, the tree, and the nearby field station operated as aid Monument personnel in reconstructing the paleoen- by the Oregon Museum of Science and Industry (OMSI), vironment of the John Day basin for their public exhibits. are named for Alonzo W. “Lon” Hancock, a devoted amateur paleontologist who collected extensively in John Day Basin MATERIALS AND METHODS in the 1950s and 60s, especially in the Clarno Formation Collections (Ashwill 1987). Samples were obtained during the summers of 1970 and Bestland et al. (1999) place the Hancock Canyon floras 1971, prior to the collecting restrictions imposed when this in the same subhorizon of the Clarno Formation as the Nut area became part of the John Day Fossil Beds National Monu- Beds and consider the two floras to be essentially coeval, ment. Specimens, slides, and detailed locality information are although the beds cannot be physically traced from one to archived at the Florida Museum of Natural History. Although the other due to an intervening dacite dome. On the other the woods occur in a single horizon, they are exposed in dif- hand, Hanson (1996, and pers. comm. 2014) maps the Han- ferent outcrops within a 0.2 km radius of the Hancock Tree cock Canyon flora in a higher stratigraphic level (his unit C), (N44.92884°, W120.415686°), with the following locality 106 PALEOBIOS, VOL. 30, NUMBER 3, APRIL 2014 numbers: UF48 (outcrop B); UF49 (outcrop C); UF68 and as listed in Gregory 1980, 1994) and the on-line Kew (outcrop D), UF69 (outcrop E). Samples are cataloged Micromorphology Database. with the 5-digit specimen number of the Florida Museum of Natural History at University of Florida (UF) preceded SYSTEMATIC PALEONTOLOGY by the UF locality number. Original field numbers (e.g., C1, The Hancock Tree indicating first sample collected from outcrop C) are also family: hamamelidaceae R. Br. 1818 indicated. Samples for thin sections were not taken from all subfamily: exbucklandioideae Harms 1930 of the Hancock Canyon logs, and these logs are referred to cf. Hamamelidoxylon uniseriatum Wheeler and by their field number only. Manchester 2002 Sample preparation (Figs. 1–6) A diamond lapidary saw was used to cut thick sections Description—The growth rings are distinct and marked by (wafers) of transverse, tangential, and radial surfaces. One side radially flattened fibers, with vessels at the end of a growth of the wafer was smoothed to remove saw marks, and then ring being narrower than those in the earlywood of the suc- affixed to a glass side using 24-hour transparent epoxy. The ceeding growth ring (Figs. 1, 2). Vessels are predominantly sections were then ground to an initial thickness of about 50 solitary, vessel outline is oval to angular (Figs. 1, 2), with µm, either by hand on a lapidary grinding wheel, or with the a mean tangential diameter of 55 µm (sd =-11; the range is aid of a Buehler petrographic thin section grinding machine. 31–80 µm), there are 50–82 vessels per mm2; the vessel ele- Further fine grinding was done by hand, using a glass plate ments are 874–1273 µm long (average 1062, n=12). Perfora- and a slurry of 400 grade silicon carbide grit, until they were tion plates are exclusively scalariform, with 20–36 bars per thin enough (ca 30 µm) to allow seeing anatomical details perforation plate (Fig. 3), the intervessel pits are rare because with transmitted light microscopy. Cover slips were mounted the vessels are predominantly solitary, but some scalariform using Canada Balsam to improve clarity for light microscopy. pits have been observed. Vessel-ray parenchyma pits are elongate (scalariform) and apparently with reduced borders Descriptions (Fig. 5). Fibers are non-septate, with walls medium-thick to Our descriptions of the woods generally conform to the thick. Axial parenchyma is diffuse, with strands of 5–8 cells, IAWA Hardwood List (IAWA Committee 1989), with ves- mostly 8 cells per strand. Rays are exclusively uniseriate (Fig. sel diameter and ray height averages based on 25 measure- 4) and consist predominantly of procumbent cells 24–45 cells ments; rays per mm based on 10 counts; vessels per mm2 high (Fig. 6), with an average of 22 cells (sd =11). There from counts of vessels in 10 fields of view. Relationships to are 12–17 rays per mm. Crystals were not observed. Storied extant groups were investigated using the InsideWood web structure is absent. site (InsideWood 2004-onwards; Wheeler 2011) and refer- Specimen number: UF69-47252/E13, upright stump ences found on the Kew Micromorphology Bibliography approximately 50 cm diameter at base. web site. Diameters (diam) of the logs are presented based Comments—Five of the sectioned Hancock Canyon on measurements in the field. woods have anatomy similar to the Hancock Tree. They have similar qualitative features and overlap in quantitative vessel Determining affinities features (Table 1). Eight other logs were not sectioned, but The identification procedure was begun with searches appeared similar macroscopically, having many narrow ves- of the InsideWood web site (Wheeler 2011; InsideWood sels and narrow rays; these are UF49-47372/C2 (diam=34 2004-onwards) and included consultation of descriptions in cm), UF49-47374/C4 (diam =18 cm), UF49-47376/C6 “Anatomy of the Dicotyledons” (Metcalfe and Chalk 1950, (diam =13 cm), UF49-47379/C9 (diam =46 cm), UF49- Metcalfe 1987, Cutler and Gregory 1998). Subsequently, 473781/C11 (diam=7 cm), UF49-045385/C15 (diam =12 comparisons were made to extant wood samples in the Bailey- cm), UF48-47351/B1 (diam=11 cm), UF69-47253/E14 Wetmore Laboratory of Plant Anatomy and Morphology (diam =35 cm). Stem diameters for this wood type range of Harvard University, Universiteit Leiden Branch of the from 7 to 50 cm. Nationaal Herbarium Nederlands, University of Utrecht, Affinities—Members of the Hamamelidaceae (Chunia Jodrell Laboratory of the Royal Botanic Gardens, and the H.T. Chang and Exbucklandia R.W. Br., subfamily Ex- David A. Kribs (NC State University) wood collections and bucklandoideae; Fothergilla L. and Hamamelis L., subfamily illustrations and descriptions in standard references (Ilic 1991; Hamamelidoideae Reinsch; Pentaphylacaceae Engler (Cleyera

/ Figures 1–6. The Hancock Tree. UF69-47252. 1. Distinct growth rings, vessels mostly solitary, XS, scale bar = 200 µm. 2. Growth ring boundary, fiber walls of medium thickness, diffuse axial parenchyma, XS, scale bar = 100 µm. 3. Scalariform perforation with many bars, viewed from the side, TLS, scale bar = 20 µm. 4. Exclusively uniseriate rays, vessel elements with scalariform perforation plates (PP), TLS, scale bar = 100 µm. 5. Vessel-ray parenchyma pits horizontally elongated (arrows), RLS, scale bar = 20 µm. 6. Ray composed mostly of procumbent cells, RLS, scale bar = 50 µm. XS =cross section; RLS =radial longitudinal section; TLS=tangential longitudinal section. WHEELER & MANCHESTER—EOCENE TREES FROM THE CLARNO FM., OREGON 107 108 PALEOBIOS, VOL. 30, NUMBER 3, APRIL 2014

haydenii (Felix) Süss & Müller-Stoll (Platanaceae T. Les- Table 1. Characteristics of the Hancock Canyon Hamamelida- tibudois) and Scottoxylon eocenicum Wheeler & Manchester ceae woods. MTD =mean tangential diameter of the vessels, stan- (probably order Urticales Juss.). Unfortunately, preservation dard deviation in parenthesis. V/MM2=mean number of vessels of the Hancock Canyon woods is not as good as the Nut per square mm. Beds woods. The combination of features that indicates these woods are similar to Platanoxylon haydenii and Scot- Specimen Field Log MTD V/MM2 toxylon eocenicum are given in the descriptions below. Two No. No. Diam µm additional wood types, each represented by a single sample, can be distinguished but their affinities cannot be determined UF49-47371 C1 31 cm 55 (9) µm 67 because some of the necessary diagnostic features cannot be UF49-47389 C19 > 20 cm 51 (9) µµ 85 clearly seen due to poor preservation. UF68-47260 D6 40 cm 51 (8) µm 71

UF68-47261 D7 45 cm 57 (10) µm 91 family: platanaceae T. Lestibudois 1826 UF69-47246 E1 45 cm 40 (7) µm 107 genus: platanoxylon Andreansky Emend Süss & Müller-Stoll 1977 Platanoxylon haydenii (Felix) Süss & Müller-Stoll 1977 Thunb.), and Theaceae D. Don. (Gordonia Ellis.) are the (Figs. 7–10) only extant plants with the combination of predominantly solitary vessels that are narrow and very numerous, exclu- Description—Growth rings are distinct, marked by radially sively scalariform perforation plates, scalariform intervessel narrow fibers, with differences in vessel diameter between the pitting, diffuse axial parenchyma, and exclusively uniseriate last-formed latewood and subsequent earlywood, and slightly rays. The type of vessel-ray parenchyma pitting is a useful noded rays (Fig. 7). Diffuse porous wood with vessels solitary feature for distinguishing between these woods. Cleyera dif- and in small multiples (mostly tangential or oblique) (Fig. fers from the Hancock tree because its vessel-ray parenchyma 7), the mean tangential diameter is 69 µm (sd =12) and there 2 pits are small and not elongated, while Gordonia differs as are 35 vessels per mm . Although the vessels are crowded, the vessel-ray parenchyma pits are consistently narrow and when counted using low magnification in an area that includes 2 quite elongated. Thus, this wood is assigned to the Hama- the wide rays, the values for vessels per mm are not high. melidaceae. The number of bars per perforation plate of this Vessels with scalariform perforation plates (Fig. 9), but poor fossil (20–36) is consistent with extant Exbucklandoideae preservation of the samples allowed counting bars in only a (Wheeler et al. 2010), a subfamily of large trees, whereas few perforation plates, 12–23 bars. Intervessel pits opposite the other subfamilies of Hamamelidaceae are mostly shrubs (Fig. 10), pits to parenchyma not observed, and the only to small trees. Although no leaves or fruits of Exbucklandia vessel element length obtained measured 550 µm. Fibers have been found in the Clarno Formation, infructescences of are non-septate, thick walled, and pits were not observed. this distinctive genus, now endemic to southeast Asia, have Axial parenchyma is diffuse-in-aggregate occurring as short been recognized previously from the Oligocene and Miocene interrupted uniseriate lines (Fig. 8). Rays are predominantly of the Pacific Northwest (Manchester 1999) and fruits and multiseriate, up to 22 cells wide, up to more than 4.8 mm seeds and inflorescences of the Hamamelidoideae are known high (avg. 2.7 mm high) and composed predominantly of from the Nut Beds (Manchester 1994). The Hancock Tree procumbent cells. Fewer than 4 rays per mm. Storied struc- is similar to Hamamelidoxylon uniseriatum from the nearby ture is absent and crystals were not observed. Clarno Nut Beds (Wheeler and Manchester 2002). There are Comments—UF49-47388 [C18] was the best preserved some differences in quantitative features; vessel frequency is of the Platanoxylon haydenii samples and the quantitative somewhat higher in the Nut Beds wood (72–133 per mm2) features in the description above are based on it. There than in the Hancock Tree. Axial parenchyma is more abun- are 15 other Hancock Canyon trees with the wide rays, dant in the Hancock Tree. These differences likely are related diffuse-in-aggregates axial parenchyma and crowded ves- to the larger diameter of the Hancock Tree. sels with a tendency to tangential grouping typical of Platanoxylon: UF49-47375/C5 (diam=10 cm); UF49- Additional wood types 47384/C14 (diam=18 cm); UF49-47387/C17 (diam=12 Some of Hancock Canyon trees are similar to two other cm); UF48-47352/B2 (diam=35 cm); UF48-47354/B4 species that occur in the Clarno Nut Beds: Platanoxylon (diam=32 cm); UF68-47256/D1 (diam=40 cm); UF68-

/ Figures 7–12. Additional Hancock Canyon woods. Figs. 7–10. Platanoxylon haydenii, UF69-47388. 7. Diffuse porous with distinct growth ring boundaries, marked by radially narrow fibers, vessels solitary and in small groups, XS, scale bar = 200 µm. 8. Diffuse-in-aggregates parenchyma, thick-walled fibers, XS, scale bar = 100 µm. 9. Scalariform perforation plate, RLS, scale bar = 50 µm. 10. Opposite intervessel pits (IVP). 11, 12. Scottoxylon eocenicum. UF69-47380. 11. Diffuse porous wood, vessels solitary and occasionally in radial multiples of two, solitary vessels rounded in outline, XS, scale bar = 200 µm. 12. Multiseriate rays to 5-seriate, simple perforation plates, and crowded alternate intervessel pits, TLS, scale bar = 100 µm. WHEELER & MANCHESTER—EOCENE TREES FROM THE CLARNO FM., OREGON 109 110 PALEOBIOS, VOL. 30, NUMBER 3, APRIL 2014

47262/D8 (diam=12 cm); D9 (diam=9 cm); UF68-47264/ family juglandaceae Perleb 1818 D11 (diam=12 cm;) UF69-47247/E2 (diam=15 cm); E7 (Figs. 13–15) (diam=10 cm); E8 (diam=34 cm); E9 (diam=13 cm); UF69- Description—Growth rings are distinct and marked by 47249 E10 (diam=15 cm); UF69-47250/E11 (diam=30 radially flattened cells at the growth ring boundary. Wood cm). Diameters of the Hancock Canyon Platanoxylon range is semi-ring porous with vessels solitary and in radial mul- from 9 to 40 cm. These apparently are additional occurrences tiples of 2–3, with a tendency toward a diagonal arrange- of wood of the Clarno Plane Tree (Manchester 1986), one ment of the vessels (Fig. 13). Mean tangential diameter of of the few whole plants known from the Eocene. the earlywood vessels is 121 µm (sd = 15). Vessel elements have simple perforation plates, crowded alternate interves- order: urticales Juss. 1820 sel pits, pits are angular in outline (Fig. 14), and measure genus: scottoxylon Wheeler and Manchester 2002 approximately 7.5–10 µm across. Vessel-ray parenchyma pits Scottoxylon eocenicum Wheeler and Manchester 2002 were not observed due to poor preservation. The only ves- (Figs. 11, 12) sel element length measured was 420 µm. Vessel elements Description—Diffuse porous wood with vessels solitary with thin-walled, widely spaced tyloses. Fibers medium-thick and in short radial multiples, vessels rounded to oval in out- walled, neither pits nor septae observed, but preservation is line (Fig. 11), with mean tangential diameters equal to140 poor. Possible axial parenchyma occurs in narrow apotracheal µm (sd=22) in UF49-47380 [C10] and 136 µm (sd =22) in bands. In radial section strands of cells with colored contents UF49-47386 [C16]. There are 9 vessels per mm2 in both are observed and interpreted as apotracheal axial parenchyma. samples. Perforation plates are simple, the intervessel pits are Rays are 1–4 seriate, mostly 2–3 seriate (Fig. 15), multiseri- crowded alternate, angular in outline with circular to slightly ate ray height averages 371 µm (sd = 81), with body of the oval apertures (Fig. 12), and measure 8–11 µm across. Vessel- ray composed of procumbent cells, there appears to be one ray parenchyma pits were not observed, but vessel-axial paren- row of square to upright marginal cells. There are 5-8 rays chyma pits have reduced borders and are horizontally elongate, per mm. In a few rays some slightly enlarged cells occur, and so vessel-ray parenchyma pits should be similar. Helical possibly crystalliferous. thickenings on vessel walls were not observed. The mean Specimen number: UF69-47248 [E6]. vessel element length is 305 µm (sd=51) in UF-49-47380 Affinities—The combination of semi-ring porosity, vessels [C10] and 402 (sd=97) in UF49-47386 [C16]. Fibers are solitary and in radial multiples with a tendency to a diagonal thin-medium thick walled, pits and septae were not observed. arrangement, simple perforation plates, crowded medium- Axial parenchyma is scanty paratracheal to vasicentric. Rays large alternate intervessel pits, thin-walled tyloses, narrow are mostly 3-5 seriate with uniseriate rays rare (Fig. 12). The rays, and narrow apotracheal bands occurs in the Juglanda- mean total height of multiseriate rays is 482 µm (sd =155) in ceae. Two types of Juglandaceae wood, Clarnoxylon blanchar- UF49-47380 [C10] and 758 µm (sd =259) in UF49-47386 dii Manchester & Wheeler and Engelhardioxylon nutbedensis [C16]. The rays are heterocellular with procumbent body cells Manchester (1983) occur in the Nut Beds. Idioblasts were and 1 (-2) marginal rows of square to upright cells. Storied not observed in this Hancock Canyon wood so it differs from structure is absent and crystals were not observed. Clarnoxylon Manchester & Wheeler, which has commonly Specimen numbers: UF49-47380 [C10], UF49-47386 occurring idioblasts. The preservation of this wood is poor so [C16]. it cannot be determined if occasional scalariform perforation Comments—The rays of UF49-47380 [C10] are shorter plates are present, which is a characteristic of Engelhardioxylon than rays of UF49-47386 [C16], but otherwise the samples Manchester. Five types of juglandaceous fruits occur in the are similar and we consider them to belong to the same taxon. Clarno Formation (Manchester 1994). This difference in ray size likely is related to the differences in sizes of the source plant, UF49-47380 [C10] having a Incertae Sedis diameter of 15 cm and UF49-47386 [C16] having a diameter ?araliaceae Juss. 1789 of 25 cm. Scottoxylon eocenicum was one of the most com- (Figs. 16–20) mon woods in the Nut Beds assemblage. Its general features Description—Growth rings are distinct, marked by radially coincide with those of the Moraceae and Cannabaceae, both flattened cells at the growth ring boundary and show slight families in the Urticales. differences in vessel diameters in the last-formed latewood and

/ Figures 13–20. 13–15. Hancock Canyon Woods. 13, 14. Probable Juglandaceae, UF69-47248. 13. Semi-ring porous wood with vessels solitary and in radial multiples, vessels tending to a diagonal arrangement, XS, scale bar = 200 µm. 14. Crowded alternate intervessel pits, TLS, scale bar = 50 µm. 15. Vessels with thin-walled tyloses, rays mostly 3-seriate, TLS, scale bar = 200 µm. 16–20. Incertae Sedis. Araliaceae? UF49-47378. 16. Distinct growth ring boundary, vessels solitary and in radial multiples of 2-4, solitary vessels rounded in outline, XS, scale bar = 200 µm. 17. Vessel-ray parenchyma pits, RLS, scale bar = 50 µm. 18. Simple perforation plates and crowded alternate intervessel pits, RLS, scale bar = 50 µm. 19. Scalariform perforation plate, RLS, scale bar=50 µm. 20. Rays 1-2 seriate, TLS, scale bar = 100 µm. WHEELER & MANCHESTER—EOCENE TREES FROM THE CLARNO FM., OREGON 111 112 PALEOBIOS, VOL. 30, NUMBER 3, APRIL 2014 earlywood of the next growth ring. Wood is diffuse porous most common remains are Macginitiea Wolfe & Wehr (Fig. to slightly semi-ring porous with vessels solitary and in radial 21), Platimeliphyllum N. Maslova (Figs. 22, 23), and Tro- multiples of 2 to 4, mostly 2, with a tendency to a diagonal chodendroides Berry (Figs. 24–26). The first two are extinct vessel arrangement. The solitary vessels are rounded in outline members of the Platanaceae, while the latter is considered to (Fig. 16). The mean tangential diameter of earlywood ves- be an extinct member of the Saxifragales with similarities to sels is 125 µm (sd=22) and there are 19–30 vessels per mm2 Cercidiphyllum Sieb. & Zucc. The same layer includes fruiting in the latewood. Perforation plates are simple (Fig. 18) and remains of Macginicarpa Manchester (Fig. 30, likely corre- scalariform with fewer than 10 bars or irregular with branch- sponding to Macginitiea; Manchester 1986) and Nyssidium ing (Fig. 19). Crowded alternate intervessel pits, angular in Heer (Fig. 29, likely the corresponding to Trochodendroides outline, and approximately 5 µm across (Fig. 18). Vessel-ray (Crane and Stockey 1985). Trochodendroides leaves have a parenchyma pits are similar in size to the intervessel pits, and similar pattern of venation to those of the extinct leaf type apparently have reduced borders (Fig. 17). Vessel element known as Zizyphoides Seward & Conway (Crane 1984), but lengths range from 620–920 µm (only 4 measured). Fibers the serrations are closer and more regularly spaced in the are medium thick-walled and neither pits nor septae were former. Zizyphoides and the commonly associated extinct fruit observed, but preservation is poor. The presence and distri- type Nordenskioeldia J. Sahlberg, are not known from the bution of axial parenchyma is not obvious, but appears to be Clarno Formation, although both are found in the Eocene rare. Rays 1-2 seriate, heights of 2-seriate rays variable (Fig. of Republic Washington (Pigg et al 2001). Although fossil 20), averaging 725 µm (sd=340), with a range of 316–1639 leaves occur elsewhere in Hancock Canyon, the specimens µm, likely intermixed procumbent and square cells, but dif- illustrated here were all collected from the same side canyon ficult to determine because of poor preservation. There are as the Hancock Tree (UF loc. 69). Other fragmentary leaf 6–10 rays per mm. types encountered include probable Fagaceae (Fig. 27) and Specimen number: UF49-47378 [C8] (diam = 32 cm). Theaceae (Fig. 28). Comments—The combination of distinct growth rings, vessels not exclusively solitary or tangentially arranged, DISCUSSION presence of both simple and scalariform perforation plates, The correspondence of leaf types with wood types remains alternate intervessel pits that are < 10 µm across, absence of somewhat speculative, as we have no instances of physical at- confluent and wide bands of axial parenchyma, and presence of tachment. However, the occurrence of both woods and leaves 1–3 seriate rays occurs in species of Araliaceae, Cunoniaceae R. of Platanaceae supports the likelihood that the same extinct Br., Juglandaceae, Lauraceae Juss., Myristicaceae R. Br., and genus may be represented by Macginitiea and Platanoxylon, Salicaceae Mirbel. (sensu APG III 2009). The occurrence of both of which also occur in the Nut Beds and at Yellowstone. rays more than one mm high argues against affinities with the The botanical affinities of the Trochodendroides-Nyssidium Juglandaceae and Lauraceae. The combination of a tendency plant (closely related and possibly equivalent to Joffrea Crane to diagonal vessel arrangement, semi-ring porosity and the & Stockey at the Paleocene locality of Joffre Bridge, Alberta, presence of some irregular perforation plates is more consis- Canada; Crane and Stockey 1985) have been considered likely tent with Araliaceae than with Cunoniaceae and Myristicaceae to belong with Cercidiphyllaceae Sieb. & Zucc., but none of (Metcalfe and Chalk 1950; InsideWood 2004-onwards). the associated woods correspond to modern Cercidiphyllum. Wood anatomy of the present-day woody Saxifragales overlap Associated leaf and fruit impressions in their features, and it is possible [probable] that this wood A ledge-forming siltstone about 15 to 20 cm thick at with features of the Exbucklandoideae represents the trunk the base of the lahar in which the Hancock Tree and other of the Trochodendroides-Nyssidium plant. stumps are embedded contains moderately well preserved leaf The low diversity and the sizes of the Hancock Canyon impressions that we consider to be approximately coeval with trees argue against them representing an old growth, well- the stumps and logs, possibly representing the forest litter established forest. The average diameters of the Exbucklan- layer that was inundated by the lahar. Although specimens doideae woods (29 cm, n=15) and Platanoxylon (20 cm, are difficult to excavate due to the overlying lahar, several n=15) fall in the category of small tree and sapling respec- specimens were obtained during the 1970s that bring ad- tively (http://ecoplexity.org/node/236). Some species of ditional insight to the Hancock Canyon fossil flora. The Exbucklandia are pioneers at disturbed sites (Whitmore 1973,

/ Figures 21–30. Fossil leaves and fruits from tuff bed immediately below the silicified wood horizon at outcrop E (UF loc.69). 21. Platanaceae: Macginitiea angustiloba. UF69-56182. 22. Platanaceae: Platimeliphyllum sp. UF69-56194. 23. Platimeliphyllum sp. UF69-56181, 24. Cercidiphyllaceae: Trochodendroides sp. with finely serrate margin, UF 69-56193. 25, 26. Trochodendroides sp. with glandular-toothed margin, UF 69-56199. 27. Probable fagaceous leaf with craspedodromous secondary veins closely spaced percur- rent tertiary veins and spinose teeth. UF69-56194. 28. Probable theaceous leaf with semicraspedodromous secondary veins, inter- secondary veins and finely serrate margin, UF56193. 29. Cercidiphyllaceae: Nyssidium fruits UF 69-56187. 30. Platanaceae: Globose infructescences of Macginicarpa, indicated by arrows; lower left head is attached on peduncle UF69-56192. Scale bars = 1 cm. WHEELER & MANCHESTER—EOCENE TREES FROM THE CLARNO FM., OREGON 113 114 PALEOBIOS, VOL. 30, NUMBER 3, APRIL 2014

Ohsawa 1991) and the Hancock Canyon flora may represent Hanson, C.B. 1996. Stratigraphy and vertebrate faunas of the such a site. In contrast, average trunk diameters of the 8 Bridgerian-Duchesnean Clarno Formation, north-central Or- wood types of the middle Miocene Vantage fossil wood flora egon. Pp. 206–239 in D.R. Prothero and R.J. Emry (eds.), (Wheeler and Dillhoff 2009) ranged from 20 (sapling) to 84 The Terrestrial Eocene-Oligocene Transition in North America. (giant tree) cm, with averages of four types being those of Cambridge University Press, New York. medium-sized trees and two types of large trees (Wheeler IAWA Committee. 1989. IAWA list of microscopic features for and Dillhoff 2009). hardwood identification. E.A. Wheeler, P. Baas, and P. Gasson (eds.). IAWA Bulletin n.s. 10:219–332. ACKNOWLEDGEMENTS Ilic, J. 1991. CSIRO Atlas of Hardwoods. Crawford House Press, Land owner, Catherine Maurer, kindly provided access Bathhurst. 525 pp. for collecting these fossils prior to the establishment of John InsideWood. 2004-onwards. Published on the Internet. http:// Day Fossil Beds National Monument. Former staff of Camp insidewood.lib.ncsu.edu/search. Hancock, operated by the Oregon Museum of Science and Manchester, S.R. 1981. Fossil plants of the Eocene Clarno Nut Industry, including John M. Armentrout, Joseph Jones III, Beds. Oregon Geology 43:75–81. Michael Uhtoff and Michael Houck are thanked for their sup- Manchester, S.R. 1983. Fossil wood of the Engelhardieae (Juglan- port and encouragement of fieldwork for this project during daceae) from the Eocene of North America: Engelhardioxylon the early 1970s. Alex Atkins, Scott Blanchard, Ian Gordon, gen. nov. Botanical Gazette 144:157–163. Manchester, S.R. 1986. Vegetative and reproductive morphology of We thank the Naturalis Biodiversity Center, Herbarium an extinct plane tree (Platanaceae) from the Eocene of western Division, Leiden, for access to their wood collection, with North America. Botanical Gazette 147:200–226. especial thank to Pieter Baas. This project was supported in Manchester, S.R. 1994. Fruits and seeds of the middle Eocene part by NSF grant DBI 0956415. Nut Beds Flora, Clarno Formation, Oregon. Palaeontographica Americana 58. 205 pp. LITERATURE CITED Manchester, S.R. 1999. Biogeographical relationships of North Angiosperm Phylogeny Group [A.P.G.]. 2009. An update of the American Tertiary floras.Annals of the Missouri Botanical Gar- Angiosperm Phylogeny Group classification for the orders and den 86:472– 522. families of flowering plants: APG III. Botanical Journal of the Metcalfe, C.R., and L. Chalk. 1950. Anatomy of the dicotyledons. Linnean Society 161:105–121. 2 Vols. Clarendon Press, Oxford, U.K. 1500 pp. Ashwill, M.S. 1987. Paleontology in Oregon: Workers of the past. Metcalfe, C.R. 1987. Anatomy of dicotyledons. 2nd Edition. Vol. Oregon Geology 49(12):147–153. III. Magnoliales, Illiciales, and Laurales. Clarendon Press, Ox- Bestland, E.A., P.E. Hamm, D.L.S. Blackwell, M.A. Kays, G.J. ford. 240 pp. Retallack, and J. Stimac. 1999. Geologic framework of the Ohsawa, M. 1991. Structural comparison of tropical montane rain Clarno Unit, John Day Fossil Beds National Monument, central forests along latitudinal and altitudinal gradients in south and Oregon. Oregon Geology 61(1):3–19. East Asia. Vegetatio 97:1–10. Crane, P.R. 1984. A re-evaluation of Cercidiphyllum-like plant fossils Pigg K.B., W.C. Wehr, and S.M. Ickert-Bond. 2001. Trochodendron from the British early Tertiary. Botanical Journal of the Linnean and Nordenskioldia (Trochodendraceae) from the middle Eocene Society 89:199–230. of Washington State, USA. International Journal of Plant Sci- Crane, P.R., and R.A. Stockey. 1985. Growth and reproductive ences 162:1187–1198. biology of Joffrea speirsii gen. et sp. nov., a Cercidiphyllum-like Scott, R.A. 1954. Fossil fruits and seeds from the Eocene Clarno plant from the Late Paleocene of Alberta, Canada. Canadian Formation of Oregon. Palaeontographica B 96:66–9 7. Journal of Botany 63:340–364. Wheeler, E.A. 2011. InsideWood—a web resource for hardwood Crane, P.R., S.R. Manchester, and D.L. Dilcher. 1991. Reproductive anatomy. IAWA Journal 32:199–211. and vegetative structure of Nordenskioldia (Trochodendraceae), Wheeler, E.A., and T.A. Dillhoff. 2009. The middle Miocene wood a vesselless dicotyledon from the Early Tertiary of the Northern flora of Vantage, Washington, USA.IAWA Journal (suppl. 7). Hemisphere. American Journal of Botany 78:1311–1334. 101 pp. Cutler D.F., and M. Gregory. 1998. Anatomy of the Dicotyledons. Wheeler, E.A., and S.R. Manchester. 2002. Woods of the Middle Vol. IV. Saxifragales (Sensu Armen Takhtajan 1983). 2nd edition. Eocene Nut Beds Flora, Clarno Formation, Oregon, USA. Clarendon Press, Oxford. 324 pp. IAWA Journal (suppl. 3). 188 pp. Gregory, M. 1980. Wood identification: An annotated bibliography. Wheeler, E.A., S.J. Lee, and P. Baas. 2010. Wood anatomy of the IAWA Bulletin n.s. 1:3–41. Altingiaceae and Hamamelidaceae. IAWA Journal 31:399–423. Gregory, M. 1994. Bibliography of systematic wood anatomy of Whitmore, T.C. (ed.). 1973. Tree flora of Malaya. Vol. 2. Long- dicotyledons. IAWA Journal Supplement 1. 265 pp. man, Kuala Lumpur.